Stevia, a native species of South America, is commercially important as a source of the non-caloric diterpene glycosides stevioside and rebaudioside-A. Although it has been cultivated in southern Brazil, the production is not enough to meet the domestic market demand. This study evaluated biomass accumulation, morphological and physiological characters, and steviol glycosides yield of seven stevia accessions after two cuts. A great variation for the different plant characteristics was found between the first and second cuts. There was a positive correlation between biomass production and SGs content and productivity. The overall Principal Components Analysis results in both cuts indicate that the accessions CE7 and CE14 presented great Reb-A yield, height and lodging (%). The accessions CE4 and CE12 produced high Ste yield and accessions CE6, CE8 and CE9 the highest leaf:stem ratio and low SGs. The stevia accessions showed characteristics of the interest for crop improvement for both biomass and SGs production.
Tissue culture technique can be an important approach for the rapid propagation of Humulus lupulus L. (hop plant). The present study evaluated different culture media for hop plants (cv. Columbus) in vitro shoots multiplication, as well as ex vitro rooting and plantlets establishment under field conditions at Southern Brazil. The culture medium containing the plant growth regulator thidiazuron (TDZ) resulted in greater in vitro shoots multiplications (five shoots per explant). For microcuttings ex vitro rooting, indole-3-butyric acid (IBA) application at a concentration of 3000 mg L -1 resulted in higher rooting and survival percentages during acclimatization. After 90 days of acclimatization, the plantlets were transplanted under field conditions and had their development and productivity evaluated 122 days after transplanting. Micropropagated plants achieved 100% survival under field conditions. Nitrogen supply is highly necessary for hop plants initial development at Southern Brazil. Micropropagation is a viable technique for quality plantlet production of H. lupulus cv. Columbus.
Elephantopus mollis Kunth. (Asteraceae) é uma espécie medicinal aromática, nativa da América do Sul e Central com propriedades hepatoprotetora, anti-inflamatória, antitumoral e leishmanicida. Objetivou-se avaliar a maturação, ponto de colheita, beneficiamento e armazenamento de sementes desta espécie visando contribuir com a produção do recurso fitoterápico. Coletou-se capítulos florais entre 7 e 56 dias após a antese, sendo avaliado a massa seca, teor de umidade e germinação das sementes e correlacionados com caracteres morfológicos dos capítulos florais. Avaliou-se o beneficiamento dos capítulos florais por meio de peneiras e soprador de sementes, com averiguação da pureza, peso de mil sementes, germinação e valor cultural das sementes. Determinou-se potencial germinativo de sementes armazenadas por até 18 meses à temperatura ambiente e refrigerado e correlacionado com teste de envelhecimento acelerado. O ponto de colheita ocorre aos 49 dias após a antese e pode ser identificado a campo pela coloração marrom das brácteas interflorais. Pode-se obter sementes com valor cultural acima de 80% com o uso de peneira 0,59 mm e soprador de sementes. As sementes podem ser armazenadas por 12 meses a frio sem queda do potencial germinativo. O teste de envelhecimento acelerado permite estimar a viabilidade do armazenamento das sementes por 18 meses.
Mudas de quiabeiro apresentam lenta absorção de nutrientes e há necessidade de fornecimento escalonado de minerais para evitar perdas por lixiviação e carência de nutrientes como nitrogênio e potássio. Dentre as opções disponíveis para a nutrição das mudas estão os fertilizantes de liberação lenta (FLL). Nesse sentido, o objetivo do presente trabalho foi avaliar doses de FLL no desenvolvimento de mudas de quiabeiro. A pesquisa foi realizada nas dependências do Instituto Federal Catarinense-Campus Araquari, com sementes da empresa Sakata, cultivar "Colhe Bem". O delineamento experimental foi inteiramente casualizado com seis doses de FLL e três repetições. As doses utilizadas foram 0, 2, 4, 6, 8 e 10 kg de FLL m-³ de substrato. Aos 27 dias após a semeadura foram avaliadas a altura, diâmetro de colo, número de folhas, massa seca da parte aérea, massa seca da raiz, massa seca total, relação entre massa seca da parte aérea e massa seca de raízes, relação entre altura e diâmetro de colo e índice de índice de qualidade de Dickson. Houve incrementos significativos nas variáveis observadas com a aplicação de FLL em relação ao tratamento controle, exceto para número de folhas e razão entre massa seca de parte aérea e massa seca de raízes e índice de qualidade de Dickson. O FLL constitui uma boa opção para promover o desenvolvimento de mudas de quiabeiro.
The objective of this study was to evaluate the effective temperature for overcoming the dormancy of 'Fuyu' persimmon tree buds. Stem samples were collected three times between 2013 and 2014. Stems were maintained in a climate incubator chamber at 3, 6, 9, and 12 °C. For each temperature, five numbers of additional chilling hours (CH) (0, 240, 384, 528, and 672 CH) were studied. The experimental design was completely randomized in a 5 × 4 factorial design (chilling hours × temperatures) with four replications with 10 cuttings. The maintenance of branches at cold temperatures from 3 to 12 °C intensified endodormancy of the buds when the plants were at the beginning of endodormancy. The most effective temperatures for overcome dormancy when the buds were in transition from paradormancy to endodormancy were from 3 to 6 °C. When the buds were already in endodormancy, temperatures of 3, 6, 9, and 12 °C were effective for the accumulation of cold and overcoming dormancy. The increase in the number of chilling hours from 3 to 12 °C induced budburst and the temperature of 12 °C was able to slowly induce and overcome bud dormancy.
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